The National Cancer Institute estimates that over 10 million Americans have a history of cancer. The American Cancer Society has predicted that over 1.4 million new cancer diagnoses will be made and over half a million Americans will die of cancer this year. Cancer is the second most common cause of death in the United States, exceeded only by heart disease.
Given the prevalence of various forms of cancer in this country, significant research focuses on developing new methods of diagnosis and treatment. Depending upon the type of cancer and its stage, current forms of treatment typically can include surgery, radiation, chemotherapy and/or hormonal treatments.
In recent years, research efforts also have focused on the development of cancer vaccines. Such vaccines are intended either to treat existing cancers (i.e., therapeutic vaccines) or to prevent cancer from developing (i.e., prophylactic vaccines). Therapeutic vaccines are designed to treat cancers by stimulating the immune system to recognize and attack cancer cells without damaging non-cancerous cells. Prophylactic vaccines are administered to healthy persons to stimulate their immune systems to attack cancer causing agents such as cancer causing viruses.
Currently, two vaccines have been licensed by the U.S. Food and Drug Administration to prevent viral infections that can lead to cancer. One is a vaccine which prevents infection with the hepatitis B virus, a virus associated with some forms of liver cancer; the second is a vaccine which prevents infection with two types of human papilloma virus that together cause 70 percent of cervical cancer cases.
Progress in developing therapeutic cancer vaccines has come more slowly. Efforts have been made to vaccinate cancer patients with tumor cells or tumor-associated antigens. Some of these efforts have had limited success. An example of a class of vaccines is reported in U.S. Pat. No. 5,478,556, which describes vaccinating breast cancer patients with compositions comprising a combination of extracted autologous or allogeneic breast tumor associated antigens (TAA) obtained from cancer cells, interleukin-2 (IL-2), and granulocyte macrophage colony stimulating factor (GM-CSF).